Bad security if sign off... yet can get back in due to stored profile info
When I sign off from a PC web browser it stores my profile info (username and password). When I'm logged into my profile on that computer at work I can simply select my profile to get back into my email and it logs back in without requiring password entry.
I think you should have a true sign-off, that immediately requires a password to get back in. It's less secure if the computer is not locked. Otherwise eliminate the sign off option. Forgetting the profile doesn't work either. If one uses a link to get back in, it just bypasses login.
Erik Wright commented
Have you checked to make sure your browser isn't simply remembering your login details? Easy way to test is by trying to sign in to outlook.com from another browser on the same PC.